IX 



WHEN TO HARVEST 



IN determining the age and dimensions at which a forest- 

 grown tree should be harvested for lumber there are cer- 

 tain features of tree-growth which must be taken into con- 

 sideration, if the greatest profit is to be realized. These 

 are (1) the ratio of annual increase of available wood ; (2) 

 the waste in manufacture dependent upon size ; (3) the 

 character and quality of the lumber, as affected by age and 

 size ; and (4) the age at which compound interest on the 

 investment overtakes the increase in value, whether from 

 growth or increase in price, or both. The first may be de- 

 termined mathematically, assuming that conditions of taper 

 of stems and freedom from limbs are alike. The second 

 and third may be approximately determined at any time, 

 while the last is entirely dependent upon the cost of the 

 investment and value of the product in market at the time 

 it is suggested that the forest be cut. 



(1) Except for a few unimportant purposes no tree can 

 be said to have a value in market if cut when it is less than 

 five inches in diameter two and one half feet above the 

 ground, a size when it may be said to enter the pole stage. 

 As it grows above that size it can be used for various pur- 

 poses, and the number of these purposes increases as the 

 tree grows larger and it finally passes from the pole and 

 tie class and enters upon that of the sawmill class. At all 

 diameters from five inches up to the time of its maturity, 

 the amount of wood the tree contains plays a commanding 

 part when determining its value and the time it should be 

 cut, and a knowledge of the amount and the ratio of the 

 tree's increase is essential when deciding to what dimen- 



